®
RT2857B
6A, 18V, Synchronous Step-Down Converter
General Description
The RT2857B is a high efficiency, monolithic synchronous
step-down DC-DC converter that can deliver up to 6A output
current from a 4.5V to 18V input supply. The RT2857B
current-mode architecture with external compensation
allows the transient response to be optimized over a wide
range of loads and output capacitors. Cycle-by-cycle
current limit provides protection against shorted outputs
and soft-start eliminates input current surge during start-
up. Fault condition protections include output over-current
protection, output over-voltage protection, and over-
temperature protection. The low current shutdown mode
provides output disconnection, enabling easy power
management in battery-powered systems.
Features
Ω
Ω
Low R
DS(ON)
Power MOSFET Switches 26mΩ/19mΩ
Input Voltage Range : 4.5V to 18V
Adjustable Switching Frequency : 200kHz to 1.6MHz
Current-Mode Control
Synchronous to External Clock : 200kHz to 1.6MHz
Accurate Voltage Reference 0.6V
±
1%, Over
− °
C
−40°
to 85°C
°
Monotonic Start-Up into Pre-biased Outputs
Adjustable Soft-Start
Power Good Indicator
Over-Current Protection
Over-Temperature and Over-Voltage Protection
Input Under-Voltage Lockout
RoHS Compliant and Halogen Free
Applications
High Performance Point of Load Regulation
Notebook Computers
High Density and Distributed Power Systems
Simplified Application Circuit
V
IN
C
IN
VIN
RT2857B
BOOT
C
BOOT
L
LX
R1
FB
R
COMP1
COMP
C
COMP2
GND
C
COMP1
R2
C
OUT
V
OUT
PVIN
Enable
PGOOD
R
OSC
RT/SYNC
C
SS
SS/TR
EN
PGOOD
Copyright
©
2019 Richtek Technology Corporation. All rights reserved.
is a registered trademark of Richtek Technology Corporation.
DS2857B-06
June 2019
www.richtek.com
1
RICHTEK [ RICHTEK TECHNOLOGY CORPORATION ]
